Technical Field
The present disclosure is directed to gas sensors to detect air quality.
Description of the Related Art
Air pollution is not limited to outdoor air pollution, but also occurs within structures, such as office buildings, homes, and public spaces, like airports. As stale air accumulates within a closed space, concentrations of carbon dioxide and volatile organic compounds (VOCs) may rise to harmful levels.
Air quality is an important factor in maintaining one's health. For example, some cardio-pulmonary ailments are triggered or exacerbated by poor air quality. At higher levels of air pollution, productivity may decrease due to lower levels of oxygen.
High levels of VOCs exist in many buildings constructed using engineered materials that contain glues, dyes, binding agents, adhesives, and the like. Furthermore, cleaning products, solvents, paint and other coatings, furniture, carpeting, and other chemical sources also contribute VOC pollutants. VOCs include such compounds as ethanol, toluene, benzene, formaldehyde, tetrachloroethene (TCE), and methylene chloride.
Green building practices have been introduced in an attempt to limit the use of VOCs and, in some cases, to require a higher outdoor air ventilation rate to prevent accumulation of both VOCs and CO2. Maintaining awareness of the levels of VOCs and CO2 present in ambient air is challenging. While some people are particularly sensitive to VOCs and will experience allergic reactions such as headaches, dizziness, and irritation of the eyes, nose, and throat in a high-VOC environment, most people cannot detect hazardous levels of pollution. Because VOCs and CO2 are both odorless, they are generally difficult to detect, and most buildings today are not equipped with multi-species gas sensors.